Respiratory syncytial virus (RSV) infection is a major cause of serious life-threatening lower respiratory tract disease in infants and young children under the age of three. Hospitalized children with underlying heart and lung conditions are at the most risk for severe complications and death due to infection with this agent. No effective vaccine is available, and the current antiviral drug available, has limited use. We conducted an animal study in collaboration with Ross Laboratories. They again provided us with potential antiviral compounds in a nutritional infant formula to test for their therapeutic efficiacy. Sixteen one year old rhesus monkeys were taken off of solid foods, divided into two groups, and given either of the two Abbott formulas. The animals were then given an intranasal RSV challenge and then followed for three weeks to monitor viral shedding in both the upper and lower respiratory tract to determine the efficiacy of the test formula. Infections in the upper respiratory tract of both groups appeared to be similar. Histologically, one group of animals showed more inflammation in lung histopathology that the other formula fed group. In conclusion, the nutritional formulas tested in this study were minimally effective against RSV in the lower respiratory tract of treated